21204221042000 has 160 divisors (see below), whose sum is σ = 53991863228160. Its totient is φ = 8038487001600.

The previous prime is 21204221041973. The next prime is 21204221042033. The reversal of 21204221042000 is 24012240212.

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 2899499 + ... + 7128501.

It is an arithmetic number, because the mean of its divisors is an integer number (337449145176).

Almost surely, 2^{21204221042000} is an apocalyptic number.

21204221042000 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21204221042000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26995931614080).

21204221042000 is an abundant number, since it is smaller than the sum of its proper divisors (32787642186160).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21204221042000 is a wasteful number, since it uses less digits than its factorization.

21204221042000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4229158 (or 4229142 counting only the distinct ones).

The product of its (nonzero) digits is 512, while the sum is 20.

Adding to 21204221042000 its reverse (24012240212), we get a palindrome (21228233282212).

The spelling of 21204221042000 in words is "twenty-one trillion, two hundred four billion, two hundred twenty-one million, forty-two thousand".